Flash memory is a type of long-term non-volatile storage medium that does not require power to retain data, and has advantages of high integration, fast access speed and easy to erase and rewrite, etc. Therefore, the flash memory has become the mainstream of non-volatile memory.
Depending on the structures, the flash memory can often be divided into two types: NOR flash memory and NAND flash memory. Compared to the NOR flash memory, the NAND flash memory can provide higher cell density, and can achieve higher storage density.
However, the electrical performance of the conventional NAND flash memory still needs to be improved. The disclosed device structures and methods are directed to solve one or more problems set forth above and other problems in the art.